Balltall cap
thingiverse
1-inch ball fits RAM mounts perfectly, accommodating most soda bottles - water bottles tend to slip out of the truck's cup holder. Non-food safe, so I'll experiment with using a plastic seal from a bottle cap.
Download Model from thingiverse
With this file you will be able to print Balltall cap with your 3D printer. Click on the button and save the file on your computer to work, edit or customize your design. You can also find more 3D designs for printers on Balltall cap.